Sealing ring, in particular for a hydraulic piston pump

Abstract

A sealing ring, in particular for a hydraulic piston pump, for sealing a pressure chamber which is filled with a fluid is disclosed. A sealing lip having a contour contacts a sealing surface and is movable relative thereto. The contour of the sealing lip is adapted according to the speed of the sealing lip relative to the sealing surface, such that a defined leakage of the fluid out of the pressure chamber is adjusted.

The invention claimed is: 
     
       1. A sealing ring for a hydraulic piston pump for sealing off a pressure space which is filled with a fluid, comprising:
 a sealing lip configured with a contour to bear against a sealing surface, the contour defining a first curved portion, an opposite second curved portion, and a parallel portion extending from the first curved portion to the second curved portion, the parallel portion running essentially parallel to the sealing surface, and the sealing lip being movable in relation to the sealing surface, 
 wherein the contour of the sealing lip is adapted to the speed of the sealing lip in relation to the sealing surface so that a defined leakage of the fluid out of the pressure space is set. 
 
     
     
       2. The sealing ring as claimed in  claim 1 , wherein the contour further defines at least one limb extending from one of the first curved portion and the second curved portion. 
     
     
       3. The sealing ring as claimed in  claim 2 , wherein the at least one limb is located on a side of the contour facing the pressure space and forms an angle of 55° to 80° with the sealing surface. 
     
     
       4. The sealing ring as claimed in  claim 2 , wherein the at least one limb is located on a side of the contour facing away from the pressure space and forms an angle of 10° to 25° with the sealing surface. 
     
     
       5. The sealing ring as claimed in  claim 1 , wherein the first curved portion defines a radius of curvature of 0.02 mm to 0.5 mm, the parallel portion defines a length of 0.01 mm to 1 mm, and the third curved portion defines a radius of curvature of 0.07 mm to 0.5 mm. 
     
     
       6. The sealing ring as claimed in  claim 1 , wherein the contour is configured so that it forms between two limbs a portion with a length of 0.08 mm to 0.12 mm. 
     
     
       7. The sealing ring as claimed in  claim 1 , wherein the sealing ring is configured to generate a defined lubricating film. 
     
     
       8. A method for producing a hydraulic piston pump, comprising:
 providing a piston and a cylindrical space which is delimited by a cylindrical wall, 
 inserting the piston into the cylindrical space so that the piston is retractable and extendable in the cylindrical space, 
 introducing a sealing ring between the piston and the cylindrical wall so that a sealing lip of the sealing ring bears with a contour against a sealing surface and is movable in relation to the sealing surface so that a pressure space filled with a fluid is sealed off, and 
 using the contour to form a predetermined lubricating film thickness of fluid between the sealing lip and the sealing surface during a retraction stroke of the piston in response to a retraction speed of the piston being lower than an extension speed of the piston. 
 
     
     
       9. The method as claimed in  claim 8 , wherein the contour defines a first curved portion, an opposite second curved portion, and a parallel portion extending from the first curved portion to the second curved portion, the parallel portion running essentially parallel to the sealing surface. 
     
     
       10. A piston pump comprising:
 a sealing ring configured to seal off a pressure space which is filled with a fluid, the sealing ring having a sealing lip configured to bear with a contour against a sealing surface, and the sealing ring being movable in relation to the sealing surface, the contour defining a first curved portion, an opposite second curved portion, and a parallel portion extending from the first curved portion to the second curved portion, the parallel portion running essentially parallel to the sealing surface, 
 wherein the contour of the sealing lip is based on the speed of the sealing lip in relation to the sealing surface so that a defined leakage of the fluid out of the pressure space is set. 
 
     
     
       11. The piston pump as claimed in  claim 10 , wherein the piston pump is configured to be used in a vehicle brake system.